Polarizing beam splitter (PBS) assemblies are found in a variety of optical imaging assemblies, such as front and rear projection systems, projection displays, head-mounted displays, virtual viewers, head up displays, optical computing, optical correlation, and other similar optical viewing and display systems. A PBS assembly may include at least one multilayer reflective optical polarizing film (MOF). In general, a MOF is a multi-layer polymer based film that functions as a polarizer and contains at least two different materials, at least one of which exhibits birefringence after uniaxial orientation. The MOF film is sandwiched between two prisms and functions to reflect a particular polarization of light while transmitting orthogonal polarizations. An adhesive is disposed between the MOF and a surface of at least one of the prisms to provide for structural integrity of the PBS assembly as well as provide optical coupling.
One example of a PBS assembly use is in a liquid crystal on silicon (i.e., LCOS) rear projection television system. LCOS rear projection television systems generate relatively high amounts of light energy and heat. Impingement onto the PBS assembly of such light energy levels and heat, especially over time, can have significant adverse effects on the average lifetimes of PBS assemblies. More particularly, relatively high amounts of light energy and heat can reduce transmissivity of the MOF over time.